Railway Preservation News

Railroad Radios
Page 2 of 2

Author:  Rick Rowlands [ Sun Jul 30, 2017 10:27 am ]
Post subject:  Re: Railroad Radios

If railroads go to encoded frequencies, would that not bring to an end every railfan with a scanner who monitors radio transmissions to learn about train movements? Why would that be a good thing?

Author:  crij [ Mon Jul 31, 2017 2:50 pm ]
Post subject:  Re: Railroad Radios

Encoding is good from a FCC viewpoint as they can stack more operators on a frequency, since the digital encoding would prevent most cross talk. As it is, especially since PTC was mandated, there are too few openings in the wireless frequencies due to all the things we do wirelessly. Because of the PTC mandate and regulations, FCC mandated the encoding to open up frequencies within and near the RR `band'.

IIRC, without digital squelch or encoding you need almost a full MHz separation (above and below) between radios to prevent cross talk, and even at that some electrical interference can `pull' a transmission enough to cause cross-talk. By cross-talk, in case I am using the wrong word, is when a transmission from one radio set is able to be heard on a frequency outside the one it is transmitted on.

I could be wrong on the above, but that is how it was explained to me about a year ago, by an old HAM operator.

Rich C.

Page 2 of 2 All times are UTC - 5 hours [ DST ]
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group